I have spent hundreds maybe even thousands of hours talking to all-time greats like Mel Daniels who absolutely FORCED Indiana to draft a kid like a Jonathan Bender. He would to this day flat-out tell anyone that this kid was the most remarkable thing he'd ever seen in his life. A 7-footer who could shoot it from half-court with the flick of a wrist, jump thru the roof and handle the ball like a guard. Now unfortunately for Jonathan (or maybe fortunately because he's become a real estate titan) a botched surgery ended his career and all the promise that people drooled over.
Sam Perkins? His son and twin daughters call me UNCLE. He will tell you the same thing. These kids are special. Hybrids almost. Eeeewl spoke about Centers not being able to shoot.... They can shoot, only now they play 4 and even 3. Versatile back then meant you could knock a shot down and were big.
Pick-and-Roll? Are you serious? Guys couldn't defend that shit EVER! Especially after Stockton mastered it in the 80's. It's just now that people realize that because guys are so athletic defensively that you need an advantage to get by guys (typically). If both guys are more athletic than they were 30 yrs ago, it hurts the OFFENSIVE PLAYER not the defender. This is where your logic is flawed. You are forgetting that the defender always has help and that's the OUT-OF-BOUNDS lines. As both player get faster, but the court remains the same size, you suddenly have less room to operate. Hence why pick-n-roll is used to death. Guys like Chris Paul use it on 90% of their possessions. If ran properly it's virtually indefensible with the right personnel. Did guys not know how to defend it in the 80's and 90's either? Maybe you're speaking of the 60's and 70's.
Durability. This is easily explained. Speak with any Team Trainer or doctor who's been around since the 60's like a David Craig who was still with the Pacers in the 2000's... The problem is not durability. It's mileage and size. These guys who would be stagnant centers are now wings and the body is just not equipped to take that kind of pressure on the limbs. It's almost equivalent to the analogy Eeeewl made in regard to a sprinter running a 100M at Sub-9 times. Your body will break. That's why it's typically from the knee down that there's an injury. ACL, MCL, PCL injuries are up insanely from 30 years ago. It's because these guys are doing things the body wasn't designed to do. They have added 30 pounds of muscle on average per position and you feet, knees, ankles etc.. do not change. What's the #1 injury in the NBA today? Answer: PLANTAR FASCIA! Why because it's way too much pressure on the feet. The constant running and jumping with so much weight due to added muscle etc..
Think about how much more basketball kids play now than they did. I came up in the mid-90's in HS and played against them all from Kobe to Vince to BD to KG to Bibby to whomever else was a great HS player now-pro from 93-97. You played 30-plus games with a NATIONAL schedule in HS and then you AAU program played a NATIONAL schedule with 150-200 games per summer. Sometimes as many as 5 games in a day. Then 3-4 All-American camps etc... It takes it's toll. And this is pretty much consistent from the time a kid shows promise at 12 years old. This didn't exist. Nobody was scouting 12 year olds 40 years ago en masse. It's the norm now because the business is huge and people want to catch the next best thing.
Can't handle the ball?

The dribbling exhibitions that these kids go thru etc.. are 1000x beyond anything that existed before. You mistake a reluctance to follow the rules with the inability to dribble the ball without palming it. It's a bad habit because that's what's viewed as cute and best to cross somebody etc... Tim Hardaway crossed you over, but AI fucked your whole life around the way he patted that bitch. Ask M... When J Will (aka White Chocolate pause) came into the league dudes like GP etc.. couldn't fucking cutting him off. He was way too crafty with the ball. But they've done a lot to force players to tone it down but believe me, fundamentally dribbling a basketball is a joke to these dudes. The training regimens alone for ball handling that dudes do is shit that would've had pro's jumping off a building 40 years ago and I'm talking shit that middle-school kids are doing. That Globetrotter shit is played out because everybody can do that shit now. You had your guys that could shonuff pat the the rock like Tiny, Zeke, Pistol and others but by and large it's not even close. Guys like Shammgod etc.. (tied for BEST HANDLE EVER!! with Rafer IMO to ever touch an NBA court) is doing dribbling clinics with kids now as young as 5 and they are out of this world.
Now I will agree all-day long about the mid-range jumpshot. It's a lost art and that's because dudes are dumb athletic and wanna dunk and chicks dig the long ball. It's just not something guys do and that's a shame. Because the guys who do have a sick mid-range or what I call "in-between" game like a Monta Ellis? They can fuckin score whenever they want because it's a shot that you can get and can make at a fairly high clip if you're quick and athletic. Joe Johnson is another who makes his living on mid-range jumpers (ridiculous handles too at 6'8). But Carmelo is the one who's mid-range game would dominate in ANY era. He can do too much.